Hydraulic jack



Jan.6,' 1931. F. J. MAY

HYDRAULIC JACK Filed March 27*, 1929 g (fa-M 11.2 1 @fiNEX:

Patented Jan. 6, 1931 UNITED STATES FRANK J. MAY, ST. PAUL, MINNESOTAHYDRAULIC JACK Application filed March 27, 1929. Serial No. 350,400.

My invention relates to a hydraulic hoist device particularly adaptedfor use on motor vehicles and the main object is to provide a simple,eflicient and reliable hoist operable selectively to lift either axle ofa vehicle, power for its operation being utilized from the vehiclemotor. The following specification fully discloses the operation andconstruction of my device, reference being had to the accompanyingdrawing illustrating the device in a preferred form and in which,

Fig. 1 is a longitudinal sectional side elevation of a motor vehiclewith my improved hydraulic device in operative position, the sectionbeing in a vertical plane at right side of the vehicle frame andomitting the right hand ground wheels.

Fig. 2 is an enlarged side elevation of the pump means and adjacentparts of my device,

with frame cover removed, to expose the mechanism. Fig. 3 is atransverse sectional elevation looking toward the rear axle' of avehicle having my improved hydraulic jack members, as seen from thevertical plane indicated by line 3-3 in Fig.1.

Referring to the drawing by reference nu- Inerals I have illustrated atruck-chassis including front Wheels 5, front axle 6, rear Wheels 7,rear axle 8, frame 9'and a motor 10,

with transmission 11, the main drive shaft 12, to' rear axle and theusual radiator 13, all in.

approximately correct relative positions and assembly in the usual motortruck construction. 14-is the usual draft fan mounted forward of themotor and driven by a pulley or gear 14G in turn'driven by a chain 15which engages a power-gear 16 on the crank shaft of themotor (see Fig.1).

40 My device comprises a suitable pump housing 17 suitably mounted aswith brackets 18 to adjacent fixed parts of the motor, said housinghaving horizontally spaced integral bearings 17B bored for a primarydrive shaft 4: 19 carrying, exteriorly of the housing, a drive of whichconnects with a piston rod 27 reciprocable in a pump cylinder 28 (seeFig. 2) having an intake pipe 29 leading from a suitable reservoir 30.Said cylinder has an outlet pipe 31 with a three Way valve 32 having alever 33 to regulate flow of oil or any other liquid used. For example,when oil is pumped from reservoir to pipe 31 it may be allowed tocirculate directly'through a pipe 34 to my hydraulic jack means, or whenthe pumping is completed the oil may he allowed to return through pipe34 valve 32 and a by-pass pipe 35 back to reservoir 30;

My lifting jack means comprisesipreferably two upright cylinders 36 foreach axle. one near each wheel, but illustrated in Figs. 1 and 3 on therear axle only. Each cylinder is suitably fixed rigid to the axle, andthe upper end having an intake port for pipe 34,

t he lowerend bored for guiding a piston rod 37 with a piston inside thebore (not shown) and on its lower end afoot piece 37 F.

38 is a tension coil spring with one end fixed to the upper part ofcylinder 36 (see Fig. 1) and its lower end fixedto the foot piece 37F,the tension'in the spring normally holding the piston rod inupperposition with its foot piece in spaced relation to the ground, assumingthere is no pressure in the pipe line 34. I When it is desired to raisea truck axle for the purpose of getting its wheels off the ground andfacilitate tire repairs or other work under the truck, it will bereadily seen that liquid is pumped through pipe 34 to the hoist jacks 36pressing the pistons therein downwardly until the foot pieces 37F arepushed down far enough to raise the axle. When the axle is raised as faras desired power is turned off and the axle will remain in said positionuntil it is desired to lower the axle again. Then valve 32 is 0 ened topermit the oil in pipe line 34; to ow back through pipe 35 to thereservoir and when pressure is thus reduced the coil spring 38automatically retracts and pulls up the foot piece.

Obviously it is necessary to make provision for regulating pump actionwithout stopping the motor and this maybe done in various ways. I haveillustrated drive pinion 21 as loose 011 the shaft and having its hubformed with jaw members 21J arranged to be engaged by a slidable keyedjaw clutch 39 on' shaft 19 and engaged by a lever 40 pivoted at 41 andprojecting above the housing 17.

journaled in the housing, a bevel pinion on said shaft, a reciprocatingplung r type liquid pump within the housing, ansmisslon meansintermediate said bevel pinion and the .plunger of the pump toreciprocate the latter when the drive pinion is rotated, .said

drive pinionarranged to be engaged by' the In testimony whereof I afiixmy signature.

FRANK J. MAY.

This lever 40 may be directly connected to I lever 33 of the valve 32 bya bar 4013 (Fig. 2) in such a way that when the clutch members areconnected to cause the pum to work the valve 32 permits direct flow 0oil or other liquid from pipe 31 through pipe 34 to the hydraulic jacksdescribed. Movement of lever 40 a predetermined distance disengages thejaw clutch but does not permitoil to back flow but causes cessation ofthe pump action.

A still further movement of lever 40 moves lever 33 to permit said backflow of oil. Obviously levers 40 and 33 may be operated independently byomitting bar 4013, and further, bar 40 may have any suitable operatingconnection (not shown) within reach of the.

truck driver. 7 It is clear that the gear reductions or train gears as21, 22, 238 and 24 may be varied as conditions may necessitate, such aspower available and amount of hydraulic pressure needed,so' as not tocause too great a strain on the relatively small operating parts in thehousing 17. Proportions of parts too may be varied greatly for obviousreasons {but not necessarily departing spirit of my invention.

Suitable control means in the pipe line 34 may be incorporated toselectively direct pressure to any one or pair of the lifting jacks. Forexample, a valve may be used to direct pressure to either or both of thejacks as illustrated in Fig. 3. Thus any wheel may be raised forrepairs.

I claim:

A hydraulic pump for motor vehicles 5 -04" a primary pump drive pinionexteriorly of the housing and mounted on a'drive shaft from the scopeand

